The immediate goal of the proposed is to test the hypothesis that th shared Trypanosoma cruzi-striated muscle sacroplasmic reticulum ATPase related antigen (SRA) directly induces autoimmune cardiomyopahty in inbred mice. The development of autoreactive cytotoxic T lymphocytes to syngeneic neonatal myofibers after immunization with SRA or infection with a strain of T. cruzi will be sought. Anti-syngeneic SRA antibody activity, macrophage cytotoxicity to syngenic neonatal myofibers and natural killer cell activity will also be measured. The association between these autreactive immunolgoic phenomena with the development of cardiac injury will be determined. The appearance of cardiomyopahty will be measured by histopahtologic study. The presence of tissue bound antibody will be determined by immunohistologic technique. The degree of cariomyopathy induced by transference of SRA-sensitized lymphoyctes in x-irradiated syngeneic recipients will also be determined. Results of these investigations may provide a rational basis for future study of the causative role SRA may play in the development of chronic chagasic cardiomyopathy in humans.